Aerodynamics of Toyota offered Spoilers

[CrankyOldMan]

I would have to put them all into the cosmetic category. The whole idea of a rear spoiler is to create downforce on the rear-end proportional to the speed of the vehicle. For RWD/AWD vehicles, this generates more traction on the drive wheels, allowing higher speeds through corners. For FWD vehicles, this would at best reduce oversteer--something that only happens if you have your setup tweaked just right. The other concern--aerodynamics--is usually defeated (spoiled?) by a spoiler, unless it's able to generate a turbulence pattern that reduces drag below the trunk lid. If someone has access to a relatively accurate 3D CAD model of a sedan with and without, I could run some fluid analysis on it.